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Time for a smoke? One cigarette reduces your life by 11 minuteshttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC1117323/
“Studies investigating the impact on mortality of socioeconomic and lifestyle factors such as smoking tend to report death rates, death rate ratios, odds ratios, or the chances of smokers reaching different ages. These findings may also be converted into differences in life expectancy. We estimated how much life is lost in smoking one cigarette.”

Smoking really does make you look older, a twin study confirmshttp://www.today.com/health/smoking-really-does-make-you-look-older-twin-study-confirms-8C11488197
“In what is perhaps the best detail of the study, researchers used the annual Twins Days Festival in Twinsburg, Ohio (the “Largest Annual Gathering of Twins in the World!”) to round up the 79 identical pairs they include in the report. A panel of three plastic surgery residents compared the faces of the twins, one of which had been smoking for at least five years longer than the other.”